護理師執行皮下注射，哪項因素決定進針角度？

皮下注射（subcutaneous injection）的進針角度設計旨在將藥物精確送入皮下組織層（subcutaneous tissue），避免誤入肌肉層或進入真皮層。進針角度主要取決於注射部位皮下脂肪的厚度以及針頭長度。若皮下組織較厚，可採 90 度垂直進針；若皮下組織較薄或病人極為消瘦，則需採 45 度角進針，以確保針尖到達目標皮下層。護理師必須在注射前評估皮膚皺褶（skin fold）的大小，這是決定角度的核心判斷依據。

The angle for a subcutaneous injection is determined by the thickness of the subcutaneous tissue at the injection site. Nurses should assess skin fold thickness to choose between a 90-degree angle for thicker tissue or a 45-degree angle for thinner tissue to ensure proper medication delivery.